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부품번호 | OB2536 기능 |
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기능 | High Precision CC/CV Primary-Side PWM Controller | ||
제조업체 | On-Bright Electronics | ||
로고 | |||
OB2536
High Precision CC/CV Primary-Side PWM Controller
Product Specification
GENERAL DESCRIPTION
OB2536 is a high performance offline PWM Power
switch for low power AC/DC charger and adaptor
applications. It operates in primary-side sensing
and regulation. Consequently, opto-coupler and
TL431 could be eliminated. Proprietary Constant
Voltage (CV) and Constant Current (CC) control is
integrated as shown in the figure below.
In CC control, the current and output power setting
can be adjusted externally by the sense resistor
Rs at CS pin. In CV control, multi-mode operations
are utilized to achieve high performance and high
efficiency. In addition, good load regulation is
achieved by the built-in cable drop compensation.
Device operates in PFM in CC mode as well at
large load condition and it operates in PWM with
frequency reduction at light/medium load.
OB2536 offers power on soft start control and
protection coverage with auto-recovery features
including Cycle-by-Cycle current limiting, VDD
OVP, VDD clamp and UVLO. Excellent EMI
performance is achieved with On-Bright
proprietary frequency shuffling technique.
High precision constant voltage (CV) and constant
current (CC) can be achieved by OB2536.
.
FEATURES
5% Constant Voltage Regulation, 5%
Constant Current Regulation at Universal AC
input
Primary-side Sensing and Regulation Without
TL431 and Opto-coupler
Programmable CV and CC Regulation
Adjustable Constant Current and Output
Power Setting
Built-in Secondary Constant Current Control
with Primary Side Feedback
Built-in Adaptive Current Peak Regulation
Built-in Primary winding inductance
compensation
Programmable Cable drop Compensation
Power on Soft-start
Built-in Leading Edge Blanking (LEB)
Cycle-by-Cycle Current Limiting
VDD Under Voltage Lockout with Hysteresis
(UVLO)
VDD OVP
VDD Clamp
APPLICATIONS
Low Power AC/DC offline SMPS for
Cell Phone Charger
Digital Cameras Charger
Small Power Adaptor
Auxiliary Power for PC, TV etc.
Linear Regulator/RCC Replacement
OB2536 is offered in DIP8 package.
Fig.1. Typical CC/CV Curve
TYPICAL APPLICATION
©On-Bright Electronics
Confidential
-1-
Preliminary Datasheet
OB_DOC_DS_253600
BLOCK DIAGRAM
OB2536
High Precision CC/CV Primary-Side PWM Controller
©On-Bright Electronics
Confidential
-4-
Preliminary Datasheet
OB_DOC_DS_253600
4페이지 OB2536
High Precision CC/CV Primary-Side PWM Controller
OPERATION DESCRIPTION
OB2536 is a cost effective PWM power switch
optimized for off-line low power AC/DC
applications including battery chargers and
adaptors. It operates in primary side sensing
and regulation, thus opto-coupler and TL431
are not required. Proprietary built-in CV and CC
control can achieve high precision CC/CV
control meeting most adaptor and charger
application requirements.
z Startup Current and Start up Control
Startup current of OB2536 is designed to be
very low so that VDD could be charged up
above UVLO threshold and starts up quickly. A
large value startup resistor can therefore be
used to minimize the power loss in application.
z Operating Current
The Operating current of OB2536 is as low as
2.5mA. Good efficiency is achieved with the
low operating current together with ‘Muti-mode’
control features.
z Soft Start
OB2536 features an internal soft start to
minimize the component electrical over-stress
during power on startup. As soon as VDD
reaches UVLO (OFF), the control algorithm will
ramp peak current voltage threshold gradually
from nearly zero to normal setting of 0.90V.
Every restart is a soft start.
z CC/CV Operation
OB2536 is designed to produce good CC/CV
control characteristic as shown in the Fig. 1.
In charger applications, a discharged battery
charging starts in the CC portion of the curve
until it is nearly full charged and smoothly
switches to operate in CV portion of the curve.
In an AC/DC adapter, the normal operation
occurs only on the CV portion of the curve.
The CC portion provides output current limiting.
In CV operation, the output voltage is regulated
through the primary side control. In CC
operation mode, OB2536 will regulate the
output current constant regardless of the output
voltage drop.
z Principle of Operation
To support OB2536 proprietary CC/CV control,
system needs to be designed in DCM mode for
flyback system (Refer to Typical Application
Diagram on page1).
In the DCM flyback converter, the output
voltage can be sensed via the auxiliary winding.
During MOSFET turn-on time, the load current is
supplied from the output filter capacitor Co. The
current in the primary winding ramps up. When
MOSFET turns off, the primary current transfers to
the secondary at the amplitude of
IS
=
NP
NS
⋅ IP
(1)
The auxiliary voltage reflects the output voltage as
shown in fig.2 and it is given by
V AUX
=
N AUX
NS
⋅ (VO
+ ΔV )
(2)
Where ΔV indicates the drop voltage of the
output Diode.
Fig.2. Auxiliary voltage waveform
Via a resistor divider connected between the
auxiliary winding and INV (pin 3), the auxiliary
voltage is sampled at the end of the
de-magnetization and it is hold until the next
sampling. The sampled voltage is compared with
Vref (2.0V) and the error is amplified. The error
amplifier output COMP reflects the load condition
and controls the PWM switching frequency to
regulate the output voltage, thus constant output
voltage can be achieved.
When sampled voltage is below Vref and the error
amplifier output COMP reaches its maximum, the
switching frequency is controlled by the sampled
voltage thus the output voltage to regulate the
output current, thus the constant output current
can be achieved.
z Adjustable CC point and Output Power
In OB2536, the CC point and maximumoutput
power can be externally adjusted by external
current sense resistor Rs at CS pin as illustrated in
Typical Application Diagram. The output power is
©On-Bright Electronics
Confidential
-7-
Preliminary Datasheet
OB_DOC_DS_253600
7페이지 | |||
구 성 | 총 10 페이지수 | ||
다운로드 | [ OB2536.PDF 데이터시트 ] |
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구매 문의 | 일반 IC 문의 : 샘플 및 소량 구매 ----------------------------------------------------------------------- IGBT, TR 모듈, SCR 및 다이오드 모듈을 포함한 광범위한 전력 반도체를 판매합니다. 전력 반도체 전문업체 상호 : 아이지 인터내셔날 사이트 방문 : [ 홈페이지 ] [ 블로그 1 ] [ 블로그 2 ] |
부품번호 | 상세설명 및 기능 | 제조사 |
OB2530N | High Precision CC/CV Primary-Side Power Switch | On-Bright Electronics |
OB2530P | High Precision CC/CV Primary-Side Power Switch | On-Bright Electronics |
DataSheet.kr | 2020 | 연락처 | 링크모음 | 검색 | 사이트맵 |